Ethernet

Fieldbus delivers

When I joined Control Engineering 11 years ago, one of our seasoned editors said to me, "Jane, keep an eye on that ISA SP50 committee. They're trying to develop a digital networking standard for smart communication among multiple vendors' instrumentation. It's going to be the biggest thing since 4-20 mA!"We waited.

By Jane S. Gerold April 1, 1998

When I joined Control Engineering 11 years ago, one of our seasoned editors said to me, “Jane, keep an eye on that ISA SP50 committee. They’re trying to develop a digital networking standard for smart communication among multiple vendors’ instrumentation. It’s going to be the biggest thing since 4-20 mA!”

We waited. We watched. We attended subcommittee meetings. We collected proceedings. The proceedings filled bookshelves. And still no digital communication standard.

Then in 1994 the Fieldbus Foundation was formed with the charter to develop a single international, interoperable fieldbus standard , much of it based on SP50 committee work. FF members claim to supply 85% of the world’s instrumentation devices.

In 1996, after adoption of the OSI model-based H1 process network standard, FF members announced fieldbus-compatible instruments at industry trade shows. But there were problems. Not all of the products were “interoperable.” Some of the multiple-vendor devices could not communicate on a single network segment. FF vowed to perfect its interoperability tester.

In 1997, FF sought IEC (International Electrotechnical Commission) approval of its FOUNDATION fieldbus as an international standard. More problems. Industry politics, alleged protectionism, and even a fax machine glitch, resulting in a vote disqualification, defeated the proposal. FF launched an appeal.

Throughout this process, FF wrestled with requirements for its H2 high-speed communication standard. Proprietary standards were proposed—and rejected. More politicking, more posturing. FF announced a newly funded effort to develop an acceptable standard. More waiting.

The breakthrough

On March 5 at its 1998 General Assembly, Fieldbus Foundation made several major announcements that address the above concerns.

First, the group formally accepted its Interoperability Test Kit, which was developed by the Fraunhofer Institute. The test system ensures device interoperability down to the level of embedded, distributed control strategies.

FF’s second announcement was that IEC voted to count the 1997 disputed ballot. This paves the way for eventual IEC and Cenelec approval of FF’s Data Link Layer standards.

Third, FF announced that it has adopted Fast Ethernet (100M Bytes/sec) as its H2 protocol. FF has overcome individual member interests to promote a cost-effective, available, and de facto industry standard.

But the real breakthrough for FF came in the second half of the General Assembly, when users of the technology extolled its benefits. Among those listed were reduced wiring costs, better diagnostics, improved maintenance, and increased flexibility.

A variety of applications were represented, from oil production to steam generation to waste water processing. All had a common message—FOUNDATION fieldbus works!

Duane Toavs, ARCO instrument and control engineer, put it best when he said, “We knew in the mid-80s that there was oil in our West Sak field on Alaska’s North Slope, but to pay for the project, oil would have to reach $30/barrel. Even though oil never got to that price, today’s fieldbus technology makes the project economically feasible.”

Well done, Fieldbus Foundation.

Author Information
Jane S. Gerold, Editorial Director jgerold@cahners.com